CN116711400A - Base station and wireless communication method - Google Patents

Abstract

A base station, comprising: a control unit that controls RAN paging processing for a terminal in an RRC inactive state; and a transmitting unit that includes information related to eDRX (Extended Discontinuous Reception) in the RAN paging processing for the above-mentioned terminal The RAN paging information element of the configuration information is sent to other base stations connected through a predetermined interface.

Description

Base station and wireless communication method

Cross References to Related Applications

This application claims priority to Japanese Patent Application No. 2021-004107 filed on January 14, 2021, the entire contents of which are incorporated herein by reference.

technical field

The present disclosure relates to a base station and a wireless communication method.

Background technique

In the 3rd Generation Partnership Project (3GPP) of the International Organization for Standardization, long-term evolution (LTE) as the 3.9th generation radio access technology (RAT: Radio Access Technology) and LTE-Advanced (LTE-Advanced) as the 4th generation RAT ), as the 15th release of New Radio (NR: New Radio) of the 5th Generation (5G: Fifth Generation) RAT is standardized (for example, Non-Patent Document 1).

In addition, in LTE (Long Term Evolution), a technology called extended discontinuous reception (eDRX: extended Discontinuous Reception) is considered in consideration of terminals whose power consumption is further restricted, such as Internet of Things (IoT: Internet of Things) devices. Introduced, eDRX cuts power consumption by limiting the time period in which wireless signals can be received (for example, Non-Patent Document 2).

prior art literature

non-patent literature

Non-Patent Document 1: 3GPP TS 38.300V15.11.0 (2020-09)

Non-Patent Document 2: 3GPP TS 36.300V15.12.0 (2020-12)

Contents of the invention

Currently, in 3GPP, discussions have begun on the assumption of functions of new IoT-oriented terminals that use NR for wireless access. Additionally, features under discussion include the aforementioned eDRX as well. Also, in NR, unlike LTE, it is specified that the terminal can transition to a state called RRC inactive (RRC_INACTIVE) in addition to RRC connected (RRC_CONNECTED) and RRC idle (RRC_IDLE). Therefore, in NR, in the case of a terminal with a high possibility of movement, such as a terminal mounted on a vehicle, it is conceivable to transition to the RRC inactive state while operating in eDRX.

In NR, RAN paging is introduced in which a base station receiving downlink data from a core network transmits paging information when transmitting downlink data to a terminal in an RRC inactive state. However, since eDRX does not exist in current NR-related specifications, no mechanism is provided to enable RAN paging when a terminal corresponding to eDRX transitions to an RRC inactive state.

One of objects of the present disclosure is to provide a base station and a wireless communication method enabling RAN paging even when a terminal corresponding to eDRX transitions to an RRC inactive state.

A base station according to one aspect of the present disclosure has a control unit and a transmission unit, the control unit controls the RAN paging process for the terminal in the RRC inactive state; the transmission unit will include eDRX (extended The RAN paging information element of the configuration information related to DiscontinuousReception) is sent to other base stations connected through a predetermined interface.

According to an aspect of the present disclosure, it is possible to provide a base station and a wireless communication method capable of performing RAN paging even when a terminal corresponding to eDRX transitions to an RRC inactive state.

Description of drawings

FIG. 1 is a diagram showing an example of a wireless communication system according to the present embodiment.

FIG. 2 is a diagram for explaining DRX operation at the time of paging.

FIG. 3 is a diagram for explaining eDRX operation during paging.

FIG. 4 is a diagram showing an example of a hardware configuration of each device in the wireless communication system.

FIG. 5 is a diagram showing an example of a functional configuration of a terminal.

FIG. 6 is a diagram showing an example of a functional configuration of a base station.

FIG. 7 is a sequence diagram showing an example of processing steps related to eDRX.

FIG. 8 is a diagram showing an example of a specification modification of the 3GPP specification.

FIG. 9 is a diagram showing an example of a specification modification of the 3GPP specification.

FIG. 10 is a diagram showing an example of a specification modification of the 3GPP specification.

FIG. 11 is a diagram illustrating an example of a specification modification of the 3GPP specification.

FIG. 12 is a diagram showing an example of a specification modification of the 3GPP specification.

FIG. 13 is a diagram illustrating an example of a specification modification of the 3GPP specification.

FIG. 14 is a diagram illustrating an example of a specification modification of the 3GPP specification.

Detailed ways

Embodiments of the present disclosure will be described below with reference to the drawings. In addition, in each figure, components attached with the same reference numerals have the same or similar structures.

<System configuration>

FIG. 1 is a diagram illustrating an example of an outline of a radio communication system according to the present embodiment. As shown in FIG. 1 , a wireless communication system 1 may include a terminal 10 , a base station 20 , and a core network 30 . In addition, the numbers of terminals 10 and base stations 20 shown in FIG. 1 are merely examples, and are not limited to the numbers shown.

As a radio access technology (RAT) of the wireless communication system 1 , for example, NR is conceivable but not limited to, and various RATs such as LTE, LTE-Advanced, or a sixth-generation or later RAT can be used.

The terminal 10 is, for example, a predetermined terminal or device such as a smartphone, a personal computer, a vehicle-mounted terminal, a vehicle-mounted device, a stationary device, or a telematics control unit (TCU: Telematics control unit). The terminal 10 may also be called a user equipment (UE: User Equipment), a mobile station (MS: Mobile Station), a terminal (User Terminal), a radio apparatus (Radio apparatus), a subscriber terminal, an access terminal, and the like. Terminal 10 may be of a mobile type or a stationary type. As a RAT, the terminal 10 can be configured to be able to communicate using NR, for example.

Here, in the 17th version of NR, the functions supporting the following terminals are discussed: the high-speed and large-capacity (enhanced MobileBroadband: eMBB), low-latency and highly reliable communication (Ultra -reliable and Low LatencyCommunications: URLLC) terminals have lower performance and price range than terminals. This terminal is also called a reduced capability (Reduced capability: RedCap) terminal, device, etc., and is assumed to be used in, for example, an industrial wireless sensor, a surveillance camera (video serviceilance), a wearable device, and the like.

It is assumed that the performance of the RedCap terminal is higher than that of a low power wide area communication (Low PowerWide Area: LPWA) oriented terminal, and the carrier used by the RedCap terminal may be, for example, a bandwidth of 20 MHz, 50 MHz or 100 MHz. In addition, in LPWA, there are, for example, category 1, Long Term Evolution for Machine-type-communication (LTE-M) that operates with an LTE-based RAT, and narrowband Internet of Things (NB-IoT). The maximum bandwidth of category 1 is 20MHz, the maximum bandwidth of LTE-M is 1.4MHz (6RB), and the maximum bandwidth of NB-IoT is 180kHz (1RB). As such, it is conceivable to use RedCap terminals as mid-range terminals between eMBB-oriented, URLLC-oriented and LPWA-oriented. The terminal 10 according to this embodiment also includes a RedCap terminal and an LPWA-oriented terminal.

The base station 20 forms one or more cells C, and communicates with the terminal 10 using the cells C. Cell C may also be called interchangeably with serving cell, carrier, component carrier (Component Carrier: CC), and the like. The base station 20 may be called gNodeB (gNB), en-gNB, Next Generation-Radio Access Network (NG-RAN) node, eNB (E-UTRAN NodeB), ng-eNB (next-generation eNB) ), low-power node, central unit (CU), distributed unit (DU), gNB-DU, remote radio head (RRH), integrated access and backhaul (Integrated Access and Backhaul/Backhauling: IAB) node etc. The base station 20 is not limited to one node, but may be composed of a plurality of nodes (for example, a combination of a lower node such as a DU and a higher node such as a CU). The base stations 20 can be connected to each other through a predetermined interface. The predetermined interface may be an Xn interface, or an X2 interface in LTE or LTE-Advanced, or an interface specified in the sixth generation or later for connecting base stations 20 to each other.

The core network 30 is, for example, a core network (5G Core Network: 5GC) corresponding to NR, but is not limited thereto. Devices on the core network 30 (hereinafter also referred to as “core network devices”) perform mobility management such as paging and location registration of the terminal 10 . The core network device can be connected to the base station 20 via a predetermined interface (eg S1 or NG interface).

The core network device includes at least one of the following multiple functions: access and mobility management function (Access and Mobility Management Function: AMF) for managing information related to access and mobility management, session management function (Session Management Function) for session management Function: SMF), User Plane Function (User Plane Function: UPF) for U-plane transmission control, Network Slice Selection Function (NetworkSlice Selection Function: NSSF) for managing network slices, etc. The functions may be implemented in one or more physical or logical devices.

In the wireless communication system 1 , a terminal 10 receives a downlink (downlink: DL) signal from a base station 20 and/or transmits an uplink signal (uplink: UL) to the base station 20 . More than one carrier can be configured in the terminal 10 . The bandwidth of each carrier is, for example, 5 MHz to 400 MHz. One carrier can be configured with one or more bandwidth parts (Bandwidth Part: BWP). A BWP has at least a portion of the bandwidth of the carrier.

In the following description, a Physical Downlink Control Channel (PDCCH) will be described as an example of a downlink control channel, but the name of the downlink control channel is not limited to PDCCH, as long as it is used The channel used for transmission of downlink control information (Downlink Control Channel: DCI) may be used. In addition, the downlink control information may also be DCI ( Downlink Control Information), whose name is not limited to DCI.

In addition, in the following description, a physical downlink shared channel (Physical Downlink Shared Channel: PDSCH) will be described as an example of the downlink shared channel. The channel of call information is sufficient, and its name is not limited to PDSCH.

(existing eDRX technology)

The conventional eDRX (Extended DRX) technology defined in LTE will be described. In LTE, a subframe (Subframe) with a duration of 1 ms, a radio frame (Radio Frame) with a duration of 10 ms, and a superframe (Hyperframe) with a duration of 10.24 seconds are defined. The position of the radio frame is represented by a system frame number (SystemFrameNumber: SFN) numbered 0 to 1023. In addition, in order to manage a time longer than 1024 radio frames, superframes having the length of SFN numbers 0 to 1023 (that is, 10.24 seconds) are also defined. A hyperframe is represented by an H-SFN (Hyper-SFN (System Frame Number)) numbered 0 to 1023.

FIG. 2 is a diagram for explaining a discontinuous reception (DRX: Discontinuous Reception) operation during paging. As shown in FIG. 2 , the terminal 10 in the RRC_IDLE state monitors downlink control channel candidates (PDCCH candidates) at a period called a paging occasion (Paging Occasion: PO) to receive a paging signal. When the terminal 10 operates according to the DRX configuration, the base station 20 transmits a paging signal during a PO period, and does not transmit a paging signal during other periods. The terminal 10 that has received the paging signal within the PO period establishes communication with the base station 20, and transitions to the RRC_CONNECTED state. There is one PO for each DRX cycle (cycle). The longest DRX cycle is 2.56 seconds.

FIG. 3 is a diagram for explaining eDRX operation during paging. As shown in FIG. 3 , the RRC-idle terminal 10 monitors downlink control channel candidates during a PO period existing within a period called a paging time window (Paging Time Window: PTW), thereby receiving a paging signal. One PTW is configured in a superframe called a paging hyperframe (PH). There is one PH per eDRX cycle. For a terminal 10 that is NB-IoT, the eDRX cycle is up to 2.91 hours (that is, 1024 superframes), and for a terminal 10 other than NB-IoT, the eDRX cycle is up to about 44 minutes (that is, 256 superframes).

When the terminal 10 operates according to the eDRX configuration, the base station 20 transmits a paging signal during the PTW period and during the PO period, and does not transmit a paging signal during other periods. The terminal 10 that has received the paging signal establishes communication with the base station 20 and transitions to the RRC_CONNECTED state.

Here, PH is H-SFN satisfying Formula 1 below.

(Formula 1)

H-SFN mod T _{eDRX, H} = (UE_ID_H mod T _{eDRX, H} )

T _eDRX , where H represents an eDRX cycle, is configured to have a length that is an integer multiple of a superframe. UE_ID_H is a hash ID (Hashed ID) determined based on S-TMSI (SAETemporary Mobile Subscriber Identity: SAE Temporary Mobile Subscriber Identity) or 5G-S-TMIS (5G S-Temporary Mobile Subscriber Identity: 5G S-Temporary Mobile Subscriber Identity) The highest 10 or 12 digits.

SFN, which is the start position (PTW_start) (start timing) of PTW, is represented by Equation 2 and Equation 3 below.

(Formula 2)

SFN=256*i _eDRX

(Formula 3)

i _eDRX = floor(UE_ID_H/T _{eDRX, H} ) mod 4

SFN which is the end position (PTW_end) (end timing) of PTW is represented by Equation 4 below.

(Formula 4)

SFN=(PTW_start+L*100-1) mod 1024

L is the time length of PTW (Paging Time Window length: paging time window length), which is configured in the terminal 10 through a message from a higher layer (RRC (Radio Resource Control) or NAS (Non Access Stratum, non-access stratum)) .

(Implementation of eDRX in NR)

When applying eDRX to NR, the following issues may be considered. First of all, using eDRX in LTE, the possible values for the starting position of PTW are limited to 4 types. Specifically, according to the above formula 2 and formula 3, the possible values of _ieDRX are 0, 1, 2 and 3, so the starting position of PTW is limited to four of SFN=0, 256, 512 and 768. However, NR is designed to be more flexible than LTE in various configurations required for wireless communication. Therefore, when implementing eDRX in NR, it is considered that the starting position of PTW should be more flexibly configured than in LTE (the first problem).

Next, in NR, an area where the terminal 10 monitors PDCCH candidates is called a search space. As the search space, a common search space (Common Search Space: CSS) configured sharedly by each terminal 10 and a specific search space (UE specific Search Space: USS) configured specifically for each terminal 10 are defined.

In NR, a search space can be configured for each BWP, but in a BWP in which a search space is not configured, it is clearly stipulated in the 3GPP specification that the terminal 10 does not monitor control channel candidates. However, since eDRX is not specified in NR, there is of course no regulation on how to operate in periods other than the PO period. In view of this situation, when eDRX is implemented in NR, it is necessary to specify a mechanism for the terminal 10 to monitor radio signals according to the configuration of DRX (second issue).

Next, a new RRC state called RRC_INACTIVE is specified in NR. Similar to RRC idle, RRC inactivity can also save power consumption of terminal 10 , but different from RRC idle, RRC inactive maintains RRC context and NAS context in terminal 10 , base station 20 and core network 30 . In addition, a RAN notification area (RNA: RAN Notification Area) is defined. The RAN notification area (RNA) is an area obtained by subdividing the tracking area (Tracking Area: TA). The base station 20 manages the RAN notification area where the terminal 10 is located. . In addition, a technique called "RAN paging" that is used when invoking the terminal 10 in the RRC inactive state is introduced, which performs paging processing in units of RAN notification areas.

In RAN paging, a paging signal is transmitted collectively from a plurality of base stations 20 constituting the RAN notification area where the terminal 10 is located. Therefore, the base station 20 needs to share various information necessary for RAN paging with other base stations 20 constituting the same RAN notification area.

In the case of a terminal 10 with a high possibility of movement, such as the RedCap terminal 10 mounted on a vehicle, it is conceivable to transition to the RRC inactive state while operating in eDRX. Therefore, in the case of implementing eDRX in NR, a mechanism is required that can perform RAN paging processing in consideration of eDRX even when the terminal 10 corresponding to eDRX transitions to the RRC inactive state (Chapter 3 subjects).

(summary of this embodiment)

In the radio communication system according to the present embodiment, in order to solve the first problem, any number of numbers that can be taken as the starting position of the PTW can be configured. In addition, in order to solve the second problem, the terminal 10 equipped with eDRX operates in such a manner that it monitors control channel candidates in the common search space for paging during PTW, and monitors control channel candidates in the common search space for Control channel candidates are not monitored in the search space. Also, in order to solve the third problem, when performing RAN paging, the eDRX-related configuration information may be notified from the base station 20 (first base station) to another base station 20 (second base station) using the Xn interface.

In the present embodiment, configuration information necessary for realizing eDRX operations, such as the eDRX cycle (eDRX cycle) and the time length of PTW (the length of the reception period), is referred to as "eDRX-related configuration information". In addition, in the following description, unless otherwise specified, the term "configuration information related to eDRX" may only refer to configuration information related to eDRX such as eDRX cycle and PTW time length, or may refer to configuration information other than those related to eDRX. In addition to relevant configuration information, it also includes configuration information required to realize DRX operations, such as configuration of DRX cycle and PO position.

＜Hardware Configuration＞

FIG. 4 is a diagram showing an example of a hardware configuration of each device in the wireless communication system. Each device in the wireless communication system 1 (for example, terminal 10, base station 20, core network 30, etc.) includes a processor 11, a storage device 12, a communication device 13 for wired or wireless communication, an input device for receiving various input actions, The input/output device 14 performs output of various information.

The processor 11 is, for example, a CPU (Central Processing Unit: Central Processing Unit), and controls each device in the wireless communication system 1 . The processor 11 can also execute various processes described in this embodiment by reading and executing a program from the storage device 12 . Each device in the wireless communication system 1 can be constituted by one or more processors 11 . In addition, each of the above devices may also be called a computer.

The storage device 12 is constituted by, for example, a storage device such as a memory, a HDD (Hard Disk Drive), and/or an SSD (Solid State Drive). The storage device 12 can store various information necessary for the processor 11 to perform processing (for example, programs executed by the processor 11, etc.).

The communication device 13 is a device for communicating via a wired and/or wireless network, and may include, for example, a network card, a communication module, a chip, an antenna, and the like. In addition, the communication device 13 may include an amplifier, an RF (Radio Frequency: Radio Frequency) device that performs processing related to wireless signals, and a BB (BaseBand: Base Band) device that performs baseband signal processing.

The RF device, for example, performs D/A conversion, modulation, frequency conversion, power amplification, etc. on the digital baseband signal received from the BB device to generate a wireless signal to be transmitted from the antenna. In addition, the RF device generates a digital baseband signal by performing frequency conversion, demodulation, A/D conversion, etc. on a wireless signal received from an antenna, and transmits it to the BB device. The BB device performs a process of converting a digital baseband signal into a packet and a process of converting a packet into a digital baseband signal.

Input/output devices 14 include input devices such as a keyboard, touch panel, mouse, and/or microphone, and output devices such as a display and/or speakers.

The hardware configuration described above is just an example. Each device in the wireless communication system 1 may omit part of the hardware shown in FIG. 4 , or may include hardware not shown in FIG. 4 . In addition, the hardware shown in FIG. 4 may consist of one or more chips.

＜Functional structure＞

(terminal)

FIG. 5 is a diagram showing an example of the functional configuration of the terminal 10 . The terminal 10 includes a receiving unit 101 , a transmitting unit 102 and a control unit 103 . All or part of the functions realized by the receiving unit 101 and the transmitting unit 102 can be realized by using the communication device 13 . In addition, all or part of the functions of the receiving unit 101 and the transmitting unit 102 and the control unit 103 can be realized by the processor 11 executing a program stored in the storage device 12 . Furthermore, the program can be stored in a storage medium. The storage medium storing the program may also be a computer-readable non-transitory storage medium (Non-transitory computerreadable medium). The non-transitory storage medium is not particularly limited, and may be a storage medium such as a USB memory or a CD-ROM.

The reception unit 101 receives a downlink signal. In addition, the receiving unit 101 may also receive information and/or data transmitted via a downlink signal. Here, "receiving" may include performing processing related to receiving at least one of the following: receiving, demapping, demodulating, decoding, monitoring, and measuring wireless signals.

In addition, the receiving unit 101 receives configuration information related to eDRX and/or configuration information related to a common search space from the base station 20 .

The transmitting unit 102 transmits an uplink signal. In addition, the transmitting unit 102 may transmit information and/or data transmitted via an uplink signal. Here, "sending" may include performing processing related to sending at least one of the following: encoding, modulation, mapping, and sending of wireless signals.

The control unit 103 performs various processes related to eDRX based on the configuration information related to eDRX received by the receiving unit 101 . In addition, the control section 103 controls based on eDRX-related configuration information such that PTW (reception period) in PH (predetermined H-SFN) monitors control channel candidates (controls reception of downlink control information).

(base station)

FIG. 6 is a diagram showing an example of the functional configuration of the base station 20 . The base station 20 includes a receiving unit 201 , a transmitting unit 202 and a control unit 203 . All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 can be realized by using the communication device 13 . In addition, the reception unit 201 and the transmission unit 202 realize all or part of the functions and the control unit 103 can be realized by the processor 11 executing the program stored in the storage device 12 . Furthermore, the program can be stored in a storage medium. The storage medium storing the program may also be a computer-readable non-transitory storage medium. The non-transitory storage medium is not particularly limited, and may be a storage medium such as a USB memory or a CD-ROM.

The receiving unit 201 receives an uplink signal. In addition, the receiving unit 201 may also receive information and/or data transmitted via the above-mentioned uplink signal. In addition, the receiving unit 201 receives configuration information related to eDRX from the core network 30 . In addition, the receiving unit 201 receives various information from other base stations 20 using the Xn interface. For example, the receiving unit 201 receives a RAN paging information element including eDRX-related configuration information from another base station.

The transmission unit 202 transmits downlink signals. In addition, the transmitting unit 202 may transmit information and/or data transmitted via the above-mentioned downlink signal. In addition, the transmitting unit 202 transmits various information to other base stations 20 using the Xn interface. In addition, the transmitting unit 202 transmits configuration information related to eDRX and/or configuration information related to a common search space to the terminal 10 .

In addition, the transmission unit 202 transmits various information to other base stations 20 . For example, the transmitting unit 202 transmits, to the other base station 20 , the RAN paging information element including the eDRX-related configuration information when executing the RAN paging process on the terminal 10 in the RRC inactive state.

The controller 203 controls the RAN paging process for the terminal 10 in the RRC inactive state. In addition, the control section 203 controls such that downlink control information is transmitted at a PTW (reception period) in a PH (predetermined H-SFN) indicated by the eDRX-related configuration information.

＜Procedures when implementing eDRX in NR＞

(order)

FIG. 7 is a sequence diagram showing an example of processing steps related to eDRX. In FIG. 7, base station 20-X and base station 20-Y constitute the same RAN notification area.

In step S100 , the terminal 10 sends a registration request (RegistrationRequest) to the core network 30 via the base station 20 . Here, the terminal 10 transmits a registration request via the base station 20-X.

In step S101, the core network 30 (such as AMF) sends a registration accept (Registration Accept) message to the terminal 10 via the base station 20-X. The registration acceptance message includes eDRX-related configuration information that should be configured in the terminal 10 . The terminal 10 stores the received eDRX-related configuration information in the storage device 12 . Registration Request and Registration Accept are also called NAS messages.

In addition, the configuration information related to eDRX is not limited to the processing steps of step S100 and step S101, and can be configured to the terminal 10 by any method. For example, RRC messages (such as (RRC Setup, RRC Reconfiguration, RRC Reestablishment, etc.)) may be used instead of NAS messages to configure the terminal 10 .

In step S102 , the base station 20 -X receives an N2 message from the core network 30 , and the N2 message includes eDRX-related configuration information configured for the terminal 10 . In addition, the N2 message refers to a message used in the interface (N2 interface) between the base station 20 and the core network 30 . The N2 message may be, for example, an initial context setup (Initial Context setup) message, a UE context modification (UE context modification) message, a handover resource allocation (Handover resource allocation) message, or a path switch request (Path switch request) message. In addition, the eDRX-related configuration information may be a part of core network assistance information for RRC inactive (Core Network Assistance Information for RRC INACTIVE).

In step S103, the terminal 10 transitions to an RRC inactive state. In the RRC inactive state, the RRC context (AS context) related to the terminal 10 is maintained in the terminal 10 and the base station 20-X.

In step S104, the core network 30 (for example, UPF) transmits downlink data (user plane data or downlink signaling) that should be transmitted to the terminal 10 to the base station 20-X.

In step S105, although the base station 20-X has received the downlink data that should be sent to the terminal 10, it detects that an event that should trigger RAN paging has occurred because the terminal 10 is in the RRC inactive state.

In step S106, the base station 20-X sends RAN paging information to other base stations 20 (here, the base station 20-Y) associated with the same RAN notification area as the base station 20-X. The other base station 20 may be referred to as a base station 20 corresponding to the RAN notification area where the terminal 10 is located. In addition, the base station 20-X includes the eDRX-related configuration information received in the processing step of step S102 in the RAN paging information and transmits it.

In step S107, the base station 20-X and the base station 20-Y send paging information to the terminal 10. Here, the base station 20-X and the base station 20-Y transmit paging information in the PTW period (more specifically, the PO period existing in the PTW period) according to the eDRX-related configuration information. Also, paging information is not transmitted during periods other than the PTW period. In addition, the base station 20 sending the paging information in the PTW period refers more specifically to transmitting the downlink information indicating the resource position of the physical downlink shared channel for sending the paging information in the common search space in the PTW period. control information.

In step S108, the terminal 10 monitors the control channel candidates in the retrieval space during the PTW period in the PH (more specifically, the PO period existing in the PTW period) according to the configured eDRX-related configuration information. When the downlink control information corresponding to the paging information is detected by monitoring the control channel candidates in the search space, the physical downlink shared channel is demodulated and decoded according to the downlink control information, thereby receiving paging information.

Here, in NR, a plurality of common search spaces shown below are defined, and are transmitted from the base station 20 to the terminal 10 using system information (SystemInformation) or a specific RRC message (RRC Setup, RRC Reconfiguration, RRC Reestablishment, etc.) configuration) configuration information related to these multiple common search spaces.

"Indicates the common search space (Type0-PDCCH CSS set) where the downlink control information of the wireless resources configured with SIB1 (System Information Block 1: System Information Block 1) is transmitted

"Indicates the common search space (Type0A-PDCCH CSSset) where the downlink control information of the radio resource configuring the system information (SIB2, SIB3, etc.) other than SIB1 is transmitted

"Common search space (Type1-PDCCH CSS set) where the downlink control information used for the reception of message 1 in the random access procedure is transmitted

"Indicates the common search space (Type2-PDCCH CSS set) where the downlink control information of the radio resource configuring the paging information is transmitted

"Indicates the common search space (Type3-PDCCH CSS set) in which the downlink control information of the radio resources where normal data such as user data is configured is transmitted

That is, the base station 20 is in the search space for paging (Type2- The downlink control signal is sent in PDCCHCSS set). In addition, the terminal 10 monitors the search space for paging among the plurality of common search spaces indicated by the configuration information related to the common search space (Type2- Control channel candidates within PDCCH CSS set).

In addition, the base station 20 may not transmit the downlink control information in the search space for paging in the period other than the PTW in the PH. In addition, the terminal 10 may not monitor control channel candidates in the search space used for paging during periods other than the PTW in the PH. By not monitoring the control channel candidates within the search space for paging during periods other than the PTW in the PH, the battery consumption of the terminal 10 can be reduced.

In addition, in this embodiment, a new common search space for paging can be defined, and the period of the search space can be changed to be the same as that of the eDRX configuration. Specifically, a new common search space used for paging may be specified using the PO period within the PTW period as a search space, and the terminal 10 monitors control channel candidates according to the configuration of the new common search space. The configuration related to the new common search space may also be notified to the terminal 10 using an RRC message or a NAS message.

(configuration of eDRX)

The eDRX-related configuration information in the processing steps of Step S101, Step S102, Step S106, Step S107, and Step S108 in FIG. 7 will be described in a number of specific examples.

[Concrete example 1 of configuration information]

The radio communication system according to the present embodiment can perform the same eDRX operation as LTE. That is, the PH may be determined according to Equation 1, the start position of the PTW may be determined according to Equation 2 and Equation 3, and the end position of the PTW may be determined according to Equation 4. In this case, the eDRX-related configuration information includes the eDRX cycle (T _eDRX,H in Equation 1 and Equation 3) and the time length of PTW (L in Equation 4). For example, in the processing step of step S106, the base station 20-X includes the eDRX-related configuration information including the information indicating the eDRX cycle and the time length of the PTW in the RAN paging information and sends it.

[Concrete example 2 of configuration information]

The wireless communication system according to the present embodiment can enable more flexible configuration of the start position of the PTW than LTE by including predetermined information related to the configuration of the start position of the PTW in configuration information related to eDRX.

For example, the predetermined information related to configuring the starting position of the PTW may include information indicating the number of starting positions of the PTW in the PH (the number of SFNs that may be configured as the starting SFN of the PTW), and the starting position of the PTW may be It is determined by inputting information indicating the number of start positions of the PTW in the PH into a predetermined calculation formula. The predetermined calculation formula may be Formula 5 and Formula 6 shown below. In addition, the end position of PTW can also be determined according to Equation 4 similarly to LTE.

(Formula 5)

SFN＝(1024 div N _PTW )*i _eDRX

(Formula 6)

i _eDRX = floor(UE_ID_H/T _{eDRX, H} ) mod N _PTW

In Equation 5 and Equation 6, N _PTW is information indicating the number of start positions of PTW in PH. For example, if N _PTW =8, then the possible value of i _eDRX is 0 to 7, so the starting position of PTW is any of the eight SFN=0, 128, 256, 384, 512, 640, 768, 896 one. In addition, when N _PTW =4, Equation 5 and Equation 6 are the same as Equation 2 and Equation 3, respectively. That is, by using Equation 5 and Equation 6, the starting position of PTW can be configured more flexibly than LTE.

When the start position of PTW is determined according to Formula 5 and Formula 6 and the end position of PTW is determined according to Formula 4, the configuration information related to eDRX includes eDRX cycle (T _{eDRX, H} in Formula 6), the time length of PTW ( L in Formula 4), the number of starting positions of PTW in PH (N _PTW in Formula 5). For example, in the processing step of step S101, the terminal 10 receives a NAS message or an RRC message with configuration information related to eDRX, and the configuration information related to eDRX includes information indicating an eDRX cycle, the time length of PTW, and the time length of PTW in PH. The number of home positions (predetermined information related to the configuration of the home positions of the PTW). In addition, in the processing step of step S106, the base station 20-X will include the information indicating the eDRX cycle, the time length of the PTW, and the number of the starting positions of the PTW in the PH (predetermined information related to the configuration of the starting positions of the PTW eDRX-related configuration information) is sent in the RAN paging information.

[Concrete example 3 of configuration information]

In the wireless communication system according to the present embodiment, the predetermined information related to the configuration of the start position of the PTW may include information specifying a wireless frame indicating the start position of the PTW. For example, the information specifying the radio frame indicating the starting position of the PTW may be information specifying a specific radio frame number, such as SFN=0, SFN=64, and so on. In addition, the eDRX-related configuration information may further include information specifying a radio frame indicating the end position of the PTW (for example, SFN=64, SFN=128, etc.). Thus, the end position of the PTW can be flexibly configured.

In this case, the eDRX-related configuration information includes an eDRX cycle, information specifying a radio frame indicating the start position of the PTW, and information specifying a radio frame indicating the end position of the PTW. For example, in the processing steps of step S101, the terminal 10 receives a NAS message or an RRC message with eDRX-related configuration information, the eDRX-related configuration information includes eDRX cycle, and specifies the radio frame indicating the starting position of PTW and information specifying the radio frame indicating the end position of the PTW. In addition, in the processing steps of step S106, the base station 20-X includes eDRX-related configuration information in the RAN paging information and sends it, the eDRX-related configuration information includes information specifying the radio frame, and information specifying the radio frame indicating the end position of the PTW.

＜Example of specification change＞

8 to 14 are diagrams showing examples of specification changes of the 3GPP specifications. The underlined portion in FIGS. 8 and 9 indicates an example of specification change related to the operation of the terminal 10 explained in the processing procedure of step S108 in FIG. 7 .

FIG. 10 shows an example of specification change when eDRX-related configuration information Paging eDRX information is added to RAN paging information explained in the processing procedure of step S106 in FIG. 7 . FIG. 11 and FIG. 12 show specific examples of eDRX parameters included in the Paging eDRX information. FIG. 11 corresponds to specific example 1 of configuration information, and FIG. 12 corresponds to specific example 2 of configuration information.

"Paging eDRX Cycle" in FIG. 11 and FIG. 12 corresponds to the eDRX cycle, and "Paging Time Window" corresponds to the time length of PTW. In addition, "Number of PTWs" in FIG. 12 corresponds to the number of start positions of PTWs in the PH.

FIG. 13 shows an example of the format of Paging eDRX information. The format shown in FIG. 13 includes the eDRX parameters shown in FIG. 11 . 13 and 14 show examples of specification changes when specifying the protocol ID of PagingDRX information.

<Summary>

According to the embodiment described above, regarding the first problem, it is possible to arrange an arbitrary number of starting positions of the PTW. Accordingly, it is possible to more flexibly configure eDRX-related operations. Also, regarding the second problem, the eDRX-equipped terminal 10 operates so as to monitor the common search space used for paging during PTW and not monitor the common search space during periods other than PTW. Accordingly, when eDRX is introduced into NR, the terminal can appropriately perform monitoring operations. In addition, the power consumption of the terminal 10 can be reduced. In addition, regarding the third problem, when performing RAN paging, it is possible to notify other base stations 20 of eDRX-related configuration information from the base station 20 . This enables RAN paging to be performed even when the eDRX-compatible terminal transitions to the RRC inactive state.

<Other Embodiments>

In the above embodiments, "monitoring the control channel candidates in the search space used for paging" may also be expressed as "monitoring the control channel candidates in the search space set configured by the paging search space information (pagingSearchSpace) ".

In the above embodiments, an example of the first time unit can also be set as 1 superframe (10.24 seconds), an example of the second time unit can be set as 1 radio frame (10 milliseconds), and the third time unit can be set as An example of the unit is set to 1 subframe (1 millisecond). The second time unit may be defined as a time shorter than the first time unit, and the third time unit may be defined as a time shorter than the second time unit. In addition, an example of a number indicating a position of a periodically repeated second time unit may be SFN, and an example of a number indicating a position of a periodically repeated first time unit may be H-SFN. For example, the H-SFN may be expressed as a first time interval indicating a position indicated by a predetermined number among periodically repeated first time intervals. In addition, the PH can also be configured as multiple superframes in the H-SFN ranging from 0 to 1023.

The various signals, information and parameters in the above embodiments may be signaled on any layer. That is, the above-mentioned various signals, information, and parameters can be replaced with signals, information, and parameters of any layer such as higher layer (such as NAS layer, RRC layer, MAC layer, etc.), lower layer (such as physical layer). In addition, the notification of the predetermined information is not limited to the explicit notification, and the predetermined information may be notified implicitly (for example, by not notifying the information or using other information).

In addition, the names of various signals, information, parameters, IEs, channels, time units, and frequency units in the above embodiments are only exemplary, and may be replaced with other names. For example, a slot may have any name as long as it is a time unit having a predetermined number of symbols (slots). In addition, RB may have any name as long as it is a frequency unit having a predetermined number of subcarriers.

In addition, the application of the terminal 10 in the above embodiments (such as RedCap, IoT-oriented, etc.) is not limited to the illustrated application, as long as it has the same function, it can be used in any application (such as eMBB, URLLC, device-to-device (D2D), Vehicle-to-everything (V2X), etc.).

In addition, the format of various information is not limited to the above-described embodiment, and may be appropriately changed to bit expressions (0 or 1), Boolean values (Boolean: true or false), integer values, characters, and the like. In addition, the singular number and the plural number in the above-mentioned embodiment may be changed mutually.

The above-described embodiments are intended to facilitate understanding of the present disclosure, not to limit interpretation of the present disclosure. The flow charts and procedures described in the embodiments, each element included in the embodiments, their arrangement, indexes, conditions, and the like are not limited to those illustrated, but can be appropriately changed. In addition, at least some of the structures described in the above embodiments may be partially replaced or combined.

Claims (10)

1. A base station, having: The control unit controls the RAN paging process for the terminal in the RRC inactive state; and The transmission unit transmits a RAN paging information element including configuration information related to eDRX (Extended Discontinuous Reception) to another base station connected through a predetermined interface in a RAN paging process for the terminal. 2. The base station according to claim 1, The other base stations are other base stations associated with the same RAN notification area as the base station. 3. The base station according to claim 1 or 2, A receiving unit that receives configuration information related to eDRX from a core network device is also included. 4. The base station according to any one of claims 1 to 3, The configuration information includes information indicating the eDRX cycle and information indicating the length of the receiving period used when the terminal performs eDRX control. 5. The base station according to claim 4, The configuration information also includes predetermined information related to the configuration of the start position of the reception period in a predetermined H-SFN (Super System Frame Number). 6. The base station according to any one of claims 1 to 5, The base station is an eNB connected to a 5G core network. 7. The base station according to any one of claims 1 to 6, The predetermined interface is an Xn interface. 8. A method of wireless communication performed by a base station, comprising: a step of controlling the RAN paging process for the terminal in the RRC inactive state; and In the RAN paging process performed on the terminal, a step of transmitting a RAN paging information element including configuration information related to eDRX (Extended Discontinuous Reception) to other base stations connected through a predetermined interface. 9. A base station, having: The receiving unit receives a RAN paging information element including configuration information related to eDRX (Extended Discontinuous Reception) from another base station connected through a predetermined interface in the RAN paging process for the terminal in the RRC inactive state; as well as The control unit controls transmission of downlink control information in a reception period in an H-SFN (Super System Frame Number) indicated by the eDRX-related configuration information. 10. A terminal having: The receiving unit receives configuration information related to eDRX (extended discontinuous reception) from the base station; and The control section controls reception of downlink control information from a predetermined The other base stations connected to the base station by the interface are sent, The other base station receives eDRX-related configuration information from the base station, and transmits the downlink control information at a reception period in the H-SFN indicated by the received eDRX-related configuration information.